1. Field of the Invention
The present invention relates to and has among its objects the provision of a novel method and apparatus for providing in combination visual and chemical stimuli for monitoring and controlling the papaya fruit fly.
2. Description of the Art
Methods developed for monitoring, controlling, and eradicating frugivorous fruit flies (Tephritidae) have relied extensively on the use of chemical attractants. These attractants include male lures for which the behavioral basis for attraction is unknown, for example, trimedlure which is used to attract male Mediterranean fruit flies; food lures; plant host attractants; and sexual and aggregating pheromones. Sex pheromones have been demonstrated or identified for several species of Tephritidae, most involving male-produced compounds attractive to females. Successful field testing of sex pheromone baited traps have been accomplished only for the female-produced pheromone of the olive fruit fly, Dacas oleae (Gmelin) (Mazomenos and Haniotakis, Journal of Chemical Ecology 11: 397-405 (1985)). Although lures of one type or another are available for most economically important species of Tephritidae, there are few, if any, good attractants for females; more potent attractants are needed for many of these flies to aid in detecting and eradicating introduced populations.
The papaya fruit fly, Toxotrypana curvicauda Gerstaecker (Diptera: Tephritidae), is the principal insect pest of papaya fruit (Carica papaya L.) throughout the tropical and subtropical areas of the Americas. Presently, no lures or attractants are available for monitoring or controlling this insect. This tephritid, unlike many other fruit fly species, is not attracted to protein hydrolysate baits because it does not feed on protenaceaous materials as an adult, and it is not attracted to any of the identified tephritid male lures such as aqueous solutions of brown or refined sucrose or to trimedlure, methyl eugenol, cue-lure, or vinegar (Shape and Landolt, Journal Georgia Entomolo. Soc. 19: 176-182 (1984)). The current monitoring method used in Florida papaya grooves is to visually check the grove perimeter where flies are concentrated near dusk. Satisfactory methods of control also are lacking for this pest species.
Landolt et al. (Annals of the Enthomological Society of America 78: 751-755 (1985)) reported that female papaya fruit flies exhibited attraction and excitatory behavior in response to male-produced volatile chemical in laboratory and wind-tunnel bioassays, which indicates that the males produce a sex pheromone.
A number of tephritid fruit flies are known to be attracted to certain colors and shapes as visual indications of foliage or fruit. It has been reported that tephritid species such as Caribbean fruit fly, Anastrepha suspensa (Loew); apple maggot fly, Rhagoletis pomonella (Walsh); European cherry fruit fly, R. cerasi (L.); Mediterranean fruit fly, Ceratiotis capitata (Wiedemann), and olive fruit fly are attracted to yellow rectangular panels, i.e. two-dimensional visual cues mimicking foliage (Greany et al., Entomol. Exp. & Appl. 21: 63-70, 1977; Prokopy, Environmental Entomology 1: 720-726, 1972; Prokopy and Boller, Journal of Economic Entomology 64: 1444-1447, 1971, and Prokopy and Economopoulos, Z. Ang. Entomol. 80: 434-437, 1976). Painted spheres, i.e., three-dimensional visual cues mimicking host fruit, have been reported as attractive to the apple maggot fly (dark red spheres); walnut hust fly, R. completa Cresson, (green spheres); and Mediterranean fruit fly (black or yellow spheres) (Prokopy, The Canadian Entomologist 109: 593-596, 1977; Riedl and Hislop, Environmental Entomology 14: 810-814, 1985, and Nakagawa et al., Entomol. Exp. & Appl. 24: 193-198, 1978). Some species have been trapped with a combination of visual stimuli of fruit or foliage and chemical (non-pheromonal) lures. Reissig et al., Environmental Entomology 11: 1294-1298, 1982, trapped apple maggot flies using synthetic apple volatiles baited with red spheres. Riedl and Hislop, supra, reported that the addition of ammonium carbonate as a food olfactory stimulus enhanced the response of walnut hust flies to yellow rectangles and green spheres but at a loss of selectivity for the target fly. Nakagawa et al., supra, reported that the addition of the chemical lure, trimedlure, to yellow rectangles or black spheres, enhanced attraction for male Mediterranean fruit flies. The only report of the combination of a visual mimic and a pheromonal lure is by Jones et al., Bull. Entomol. Res. 73: 97-106, 1983, who report the use of a component of the female-produced olive fruit fly sex pheromone and yellow panels (foliage mimic) to trap male flies. To date, no attractant or monitoring method is available for the papaya fruit fly, and methods are needed to reduce crop losses caused by this insect.